Flow line bundle and method of towing same

ABSTRACT

A flow line bundle assembly includes a plurality of conduits disposed within a tubular covering member. The tubular covering member is sealed at its ends before being placed in a body of water, so that the flow line bundle has a slight positive buoyancy when submerged in the body of water. Weights are then added to the flow line bundle to cause it to have a neutral buoyancy at a position slightly above a floor of the body of water. The flow line bundle is then towed from its point of construction, through the body of water, to the location where it is to be installed. During a first method of towing, if an obstacle located above the ocean floor is approached, a trailing tug increases a restraining force applied to the flow line bundle so as to lift it above the obstacle as the flow line bundle passes over the obstacle. A second method of towing maintains the flow line bundle at a constant depth below a surface of the body of water so that the bundle will clear any obstacles on the floor of the body of water. After the flow line bundle is connected between the subsea wellhead and a producing platform located within the body of water, the space between the conduits and the tubular covering member is flooded to sink the flow line bundle to the ocean floor and to provide heat transfer between the conduits and the tubular covering member.

This is a continuation of application Ser. No. 048,316 filed June 14,1979, now U.S. Pat. No. 4,363,566.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to flow lines located between two points within abody of water, and more particularly, but not by way of limitation, itrelates to a flow line bundle including a plurality of flow linesdisposed in a tubular covering member.

2. Description of the Prior Art

U.S. Pat. Nos. 3,677,302 and 3,526,086, both to Morgan, each showpluralities of conduits disposed within a tubular covering member. InU.S. Pat. No. 3,526,086, however, the space between the conduits and thecovering member is filled with a solid material 30, so that such a spacecould not be filled with sea water. In U.S. Pat. No. 3,677,302, thetubular covering member includes a plurality of articulated jointportions, and the covering member is not sealed at those joints, so thatthe combination of the conduits and the covering member would never bebuoyant. Furthermore, the structure disclosed in U.S. Pat. No. 3,677,302comprises a riser assembly, rather than a flow line bundle.

U.S. Pat. Nos. 4,120,168 and 4,052,862, both to Lamy, disclose a singleconduit located within a tubular covering. Spacers are connected betweenthe conduit and the covering, and a space between the conduit and thecovering may be filled with water.

The prior art includes methods of towing a tubular member through a bodyof water by constructing the tubular member so that it is neutrallybuoyant at a position located above a floor of the body of water, withweight means partially engaging the floor of the body of the water. Sucha structure is shown for example in U.S. Pat. No. 4,107,933 to Lamy.Other disclosures of that general type are shown in U.S. Pat. No.4,135,844 to Lamy, U.S. Pat. No. 4,011,729 to Kermel, U.S. Pat. No.3,262,275 to Perret and U.S. Pat. No. 4,145,909 to Daughtry.

Additionally U.S. Pat. No. 4,145,909 shows, at FIG. 8 thereof, a methodfor pulling in an end of a tubular member for connection to a subseastructure. Another apparatus for pulling in an end of a tubular memberfor connection to a subsea structure is disclosed in Paper No. OIC-3074entitled "Second End Flowline Connection Without Length Adjustment"presented at the Tenth Annual Offshore Technology Conference in Houston,Tex., during the period of May 8-11, 1978, and that same apparatus isalso disclosed in an article entitled "Laying Underwater Pipelines ByFloat and Chains Method" in the April, 1978 issue of Ocean ResourcesEngineering.

U.S. Pat. No. 2,297,165 to Ringel shows several versions of spacermembers for locating one tubular member inside another tubular member.

SUMMARY OF THE INVENTION

In connecting two points within a body of water, such as a subseawellhead and a producing platform, it is generally necessary to layseveral lines between the wellhead and the platform. The presentinvention provides an improved method of constructing and installing aflow line bundle including such a plurality of lines between the subseawellhead and the platform. A plurality of fluid conducting conduits isdisposed within a tubular covering member. A plurality of longitudinallyspaced spacer means are connected to said conduits to retain theconduits in a spaced relationship from the tubular covering member. Amanifold member including a plurality of ports is attached to each endof the conduits so as to provide fluid communication between the ends ofthe conduits and the ports of the manifold members. A cap means issealingly engaged with an end of each of the manifold members to preventwater from entering said ports.

The flow line bundle just described is constructed on land and then istowed to the installation site. The bundle has a slight positivebuoyancy when it is not hampered by additional weight other than thestructure of the bundle just described. Additional weight means such aschains or the like are then attached to the bundle to cause it to have aneutral buoyancy at a point a short distance above a floor of said bodyof water with said weight means partially engaging said floor. Then atowing tug is attached to a leading end of the flow line bundle by afirst flexible line, and a restraining tub is attached to a trailing endof the flow line bundle by a second flexible line.

The flow line bundle is then towed in a catenary fashion between the twotugs to the point of installation. This may be done by either of twobasic methods.

By a first method, the flow line bundle is towed at a short, relativelyconstant distance above the ocean floor with the chains or other weightmeans engaging the ocean floor. During the course of the towingoperation, if obstacles are encountered which are located above theocean floor, the trailing tug will increase the restraining force beingapplied to the second flexible line so as to lift the flow line bundleoff the ocean floor and cause it to "fly" over the obstacle on the oceanfloor.

The second method is similar to the first, except that the restrainingtug continually applies a restraining force during the towing operation,sufficient to maintain the flow line bundle at a controlled distancefrom the surface of the body of water. The weight means generally do notengage the ocean floor during the towing procedure of the second method.

When the bundle is finally brought to the point of installation, the capmeans are removed from the ends of the flow line bundle and the ends ofthe bundle are attached to the subsea wellhead and the producingplatform. Then the space between the conduits and the tubular coveringmember of the flow line bundle is flooded with sea water so as to causethe bundle to sink to the ocean floor.

Additionally, one of the fluid conducting conduits generally conducts arelatively high temperature fluid. The presence of the sea watersurrounding the high temperature conduit serves to transfer that heatrelatively evenly to the other conduits and to the tubular covering. Thetransfer of heat to the other conduits causes all the conduits to expandsubstantially equally due to the thermal expansion, so that relativedifferences in the thermal expansion between conduits are minimized. Thetransfer of heat to the outer covering member serves to transfer theheat completely away from the flow line bundle by conducting it throughthe covering member to the body of water.

It is therefore a general object of the present invention to provide animproved construction for a subsea flow line bundle.

Yet another object of the present invention is the provision of a subseaflow line bundle including a plurality of fluid conducting conduitsdisposed in a tubular covering member.

Another object of the present invention is the provision of an improvedmethod for towing a flow line bundle or other tubular member through abody of water.

Yet another object of the present invention is the provision of a towingmethod for a tubular member through a body of water which provides ameans for lifting the tubular member above the obstacles upon the oceanfloor.

Yet another object of the present invention is the provision of animproved method for connecting a subsea flow line bundle between twopoints within a body of water.

Other and further objects, features and advantages of the presentinvention will be readily apparent to those skilled in the art upon areading of the following disclosure in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic elevation view of the flow line bundle suspended afew feet above the ocean floor and being towed between two tugs in acatenary fashion.

FIG. 2 is a schematic elevation view of the flow line bundle of FIG. 1when the trailing tug exerts sufficient restraining force to lift theflow line bundle above an obstacle on the ocean floor as the flow linebundle is being towed. FIG. 2 also illustrates the appearance of theflow line bundle when it is being towed at a controlled depth below theocean surface.

FIG. 3 is a cross-sectional view of the flow line bundle showing theconduits located within the tubular covering member and showing one ofthe spacer members.

FIG. 4 is a side elevation view of the leading sled of the flow linebundle.

FIG. 5 is a top plan view of the sled of FIG. 4, with the floatationtanks removed to allow the other components to be more clearly seen.

FIG. 6 is an end view of the sled of FIG. 4.

FIG. 7 is a sectional view, taken along line 7--7 of FIG. 5, showing across-sectional view of one of the manifold members of the flow linebundle.

FIG. 8 is an end view of the manifold member of FIG. 7 illustrating thelocation of the various ports within the manifold member.

FIG. 9 is a schematic elevation view of the sled which has beenconnected to a pull-in line connected to the producing platform.

FIG. 10 is another schematic elevation view similar to FIG. 9, showingthe sled partially in place within the sled receiving module of theproducing platform.

FIG. 11 is another view similar to FIG. 9, showing the sled completelypulled into the sled receiving module and showing the fluid connectorconnected to the manifold member of the sled.

FIG. 12 is a schematic elevation view taken along line 12--12 of FIG. 15prior to the connection of the fluid connector to the manifold member.FIG. 12 shows the cap removing assembly in its unactuated position.

FIG. 13 is a view similar to FIG. 12 showing the cap removing assemblyin its downwardmost position with the cap engaging prongs engaged withthe tangentially extending flange of the cap.

FIG. 14 is a view similar to FIG. 12 with the cap removing assembly onceagain moved to its uppermost position having pulled the cap out ofengagement with the manifold member.

FIG. 15 is a schematic elevation view, similar to FIG. 11, illustratingthe fluid connector and illustrating the spring loaded sled lockingassembly.

FIG. 16 is an elevation view of the fluid connector, taken along line16--16 of FIG. 15.

FIG. 17 is a sectional schematic elevation view of the fluid connector,taken along line 17--17 of FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and particularly to FIGS. 1 and 2, theflow line bundle of the present invention is shown and generallydesignated by the numeral 10. Flow line bundle 10 may be a mile or morein length.

As is best shown in FIG. 3, the flow line bundle 10 includes a pluralityof fluid conducting conduits 12, 14, 16, 18, 20 and 22. The conduits12-22 are located within an outer tubular covering member 24. By way ofexample only, in one embodiment of the present invention, conduits 12and 14 are 31/2 inch diameter flow lines. Conduits 16, 18, 20 and 22 are0.84 inch diameter hydraulic control lines. Tubular covering 24 has a123/4 inch outside diameter.

Due to the remote location of the subsea well, and the difficulty ofservicing the same, it is desirable that conduits 12 and 14 beconstructed to allow pump down type service tools to pass therethrough.To that end the welds on conduits 12 and 14 should not protrude inwardpast the inner surface thereof.

A polyurethane spacer, generally designated by the numeral 26, isconnected about the conduits 12-22 and holds the same in a spacedrelationship from an inner surface of the outer covering member 24. Thespacer member 26 includes first and second spacer components 28 and 30which are connected together by a plurality of bolts (not shown), or thelike. A plurality of similar spacer members (not shown) arelongitudinally spaced from spacer member 26 at intervals ofapproximately fifteen feet along the length of the conduits 12-22.

As seen in FIG. 3, it is desirable to locate the conduits 12-22 towardthe bottom side of covering 24 so that the center of gravity of the flowline bundle is below the center of buoyancy of the flow line bundle.

Referring again to FIGS. 1 and 2, the flow line bundle 10 includes atits leading end a leading flow line sled assembly 32. At its trailingend the flow line bundle 10 includes a trailing flow line sled assembly34.

A first flexible line 36 is connected between the leading end of theflow line bundle 10 and a towing tub 38 which may also be described as apowered floating vessel. A second flexible line 40 is connected betweenthe trailing end of flow line bundle 10 and a trailing tug 42.

The flow line bundle 10 is constructed on land and the ends thereof aresealed as will later be described. The conduits and the space betweenthe conduits and the tubular covering member 24 is then generallypressurized to around 200 psig with nitrogen gas or the like. The flowline bundle 10 is constructed so as to have a positive buoyancy ofapproximately 1/2 pound per foot when submerged in the body of water 44prior to the addition of any weight means.

It is desired that when the flow line bundle 10 is being towed throughthe body of water 44, that the flow line bundle 10 float either justabove a floor 46 of the body of water 44, or at a controlled depth belowthe surface of the body of water as shown in FIG. 2. This is referred toas a buoyant off-bottom tow method.

A plurality of weight means 48 are attached to the flow line bundle 10to cause the flow line bundle to have a neutral buoyancy, at a positionsuch as that illustrated in FIG. 1, several feet above the ocean floor46, with the weight means 48 partially engaging the ocean floor. Similarweight means are shown for example in U.S. Pat. No. 4,145,909 toDaughtry.

By a first method, the flow bundle 10 is towed in the manner illustratedin FIG. 1, with the towing force being exerted by the towing tug 38 andwith the trailing tug 42 exerting slight restraining force on secondflexible line 40 to control the trailing end of flow line bundle 10.

It is not uncommon, as the flow line bundle 10 is being towed throughthe body of water 44, for obstacles such as shipwreck 49 or the like,which are located above the ocean floor 46, to be encountered. Othersuch obstacles might also include subsea pipelines (not shown) or thelike.

The present invention provides a novel method of avoiding underwaterobstruction 49 in a manner illustrated in FIG. 2. As the flow linebundle 10 approaches the obstacle 49, the trailing tug 42 increases areverse thrust thereof to increase a retarding force applied to secondflexible line 40 so as to lift the flow line bundle 10 to a position,illustrated in FIG. 2, a considerable distance above the ocean floor 46,so that the flow line 10 is located above the obstacle 49 as it passesthereover.

The manner of towing the flow line bundle 10 illustrated in FIGS. 1 and2 is often referred to as towing the flow line in a catenaryconfiguration. That is, the first and second flexible lines 36 and 40and the flow line bundle 10 roughly approximate the shape of a catenarysuspended between the leading and trailing vessels 38 and 42. Of coursethey do not form a true catenary due to the lack of flexibility and thenonuniformity of the weight distribution across the entire systemsuspended between the towing and trailing vessels, 38 and 42.

When the retarding force on the second flexible line means 40 isincreased, the shape of the catenary is changed causing it to have amuch larger radius of curvature along its various points and therebycausing the middle portion of the catenary defined by the flow linebundle 10 to be raised above the ocean floor 46.

Alternatively, by a second method, the trailing vessel 42 continuallyapplies a restraining force sufficient to maintain the flow line bundle10 at a controlled distance below the surface of the body of water 44,i.e. the flow line bundle 10 is generally maintained in theconfiguration shown in FIG. 2 throughout the towing procedure.

The specific depth below the surface at which the flow line bundle 10should be towed depends upon many factors, one of which is the roughnessof the sea at the time of the towing operation. Generally, the rougherthe surface conditions are, the greater the towing depth should be sothat the affect upon the flow line bundle 10 from the rough sea isminimized.

The depth at which the flow line bundle 10 is towed may be controlled inmany ways. One way is to measure the depth by sonic means or by pressuresensing means. Another way is to control the distance between theleading and trailing vessels 38 and 42, which may be done with the aidof a radar type apparatus located on the vessels to measure thatdistance.

Referring now to FIGS. 4-7, the leading sled 32 is thereshown. Leadingsled 32 includes a frame assembly 50 with floatation tanks 52 and 54attached thereto. Frame 50 includes lugs 53 to which flexible line 36may be attached.

FIG. 5 is a plan view of sled assembly 32 with the floatation tanks 52and 54 removed.

A manifold member 56 is attached to frame 50. Manifold member 56includes a manifold block 58 which has a plurality of ports 55, 57, 59,60, 61, and 62 disposed therethrough, as seen in FIG. 8, forcommunication with conduits 16, 18, 20, 22, 12 and 14, respectively. Itis noted that FIG. 7 is a schematic illustration, and the ports 57 and62 thereshown are actually oriented in accordance with FIG. 8. An end 64of manifold block 58 is attached to a manifold extension 66 by aclamping ring 68 which engages outwardly extending flanges 70 and 72 ofmanifold block 58 and manifold extension 66, respectively.

Manifold extension 66 includes ports 74 and 76 communicating with ports57 and 62, respectively, of manifold block 58. Stub extensions 78 and 80extend from manifold extension 66 and communicate with ports 74 and 76,respectively. Manifold extension 66 includes other ports and stubextensions corresponding to ports 55, 59, 60 and 61.

Each of the relatively smaller conduits 16, 18, 20 and 22 has an endthereof welded to a stub extension such as stub extension 78. Thisprovides fluid communication between the small conduits and one of therelatively smaller ports such as port 74 of manifold extension 66.

Each of the relatively larger conduits 12 and 14 is welded to a stubextension such as stub extension 80 to provide fluid communication withone of the relatively larger ports, for example, port 76 of manifoldextension 66.

After the welding of the conduits 12-22 to the stub extensions, such asextensions 78 and 80, of manifold extension 66 of manifold member 56, atubular covering extension 82 is then welded at its first end 84 tomanifold extension 66 and at its second end 86 to tubular covering 24.The tubular covering extension 82 may be considered to be a portion ofthe tubular covering member 24.

Another end 88 of manifold block 58 is sealingly engaged by a cap means89 when the flow line bundle 10 is first assembled. The cap means 89 isconnected to manifold block 58 by a cap retaining collar assembly 90,and prevents sea water from entering conduits 12-22 and covering 24 sothat flow line bundle 10 has a positive buoyancy when submerged inwater.

As may best be seen in FIG. 12, the cap retaining collar assembly 90includes first, second and third arcuate collar portions 92, 94 and 96.

The first arcuate collar portion 92 includes a tangentially extendingflange 98. The second and third collar portions 94 and 96 are eachhingedly connected to first collar portion 92 at hinge points 100 and102, respectively.

Each of the second and third arcuate collar assembly portions 94 and 96include radially outward extending flanges 104 and 106.

As is best seen in FIG. 7, the flanges 104 and 106 are connected by ashear bolt 108. Attached to flange 104 of arcuate portion 94 is asliding shear member 110 which includes slots 112 and 114 disposed aboutconnecting bolts 116 and 118.

The shear pin 108 may be sheared by moving sliding shear member 110longitudinally relative to cap retaining collar assembly 90. When shearbolt 108 is sheared, the second and third arcuate collar portions 94 and96 separate and the collar assembly 90 may be removed.

FIG. 8 is an enlarged view of second end 88 of manifold block 58 showingthe various ports thereof. Additionally alignment blind bores 120, 122and 124 are included for engagement with alignment stubs 125 of a fluidconductor assembly 126 attached to production platform 128. The fluidconductor assembly 126 is best illustrated in FIGS. 15-17.

After the flow line bundle 10 has been towed through the body of water44 to a location closely adjacent the two points to be connected withinthe body of water, i.e. adjacent the subsea wellhead (not shown) at oneend, and adjacent the producing platform 128 at the other end, the endsof the flow line bundle are connected to the subsea wellhead and theproducing platform 128 in substantially the following manner.

The manner of connection of the leading end of flow line bundle 10 tothe producing platform 128 will be described for the purpose of thisdisclosure. The connection of the other end is done in a similar manner.

As shown in FIG. 9, a pull-in cable 130 is connected between leadingsled 32 and a sled receiving module 132 of producing platform 128. Thepull-in cable 130 is preferrably connected between a leading noseportion of a cylindrical frame extension 134 of frame 50 of sledassembly 32, and is then threaded through a cylindrical frame extensionreceiver 136 and then is threaded through a system of pulleys 138 andguides 140 which direct the cable 130 to a position on producingplatform 128 located above the surface of the body of water 44. Then thefirst flexible line 36 is disconnected from flow line bundle 10.

The pull-in cable 130 is then retrieved, thereby pulling leading sledassembly 32 into place within sled receiving module 132. FIG. 10 showsleading sled assembly 32 partially pulled into sled receiving module 132so that the cylindrical frame extension 134 is just engaged with thecylindrical frame extension receiver 136. FIG. 11 shows leading sledassembly 32 pulled completely into its final position within sledreceiving module 132.

FIG. 15 is a view similar to FIG. 11 showing some additional componentsof the sled receiving module 132. It will be understood stood that bothFIGS. 9-11 and FIG. 15 are schematic in form and no attempt has beenmade to superimpose all of the apparatus of the sled receiving module132 in any one figure.

In FIG. 15 the leading sled assembly 32 is shown in its fully pulled-inposition, in place within sled receiving module 132. When lead sledassembly 32 is in the fully pulled-in position, a latching member 142 isresiliently urged by means of spring member 144 into engagement with alatching cam 146 of frame 50 of sled assembly 32.

FIG. 15 illustrates leading sled assembly 32 with the cap means 89 stillretained in place upon manifold member 56 by cap retaining collarassembly 90. That is the position those components will be in when theleading sled assembly 32 is first pulled into place within sledreceiving module 132. Then the other end of the flow line bundle 10 willbe similarly pulled into place within a similar sled receiving module(not shown) of the subsea wellhead assembly (not shown). It is notedthat it may sometimes be preferrable to pull-in the end adjacent thesubsea wellhead first.

The next operation which must be conducted is to remove the sealing capmeans 89 from manifold member 56 so that the manifold member 56 may thenbe connected to fluid connector assembly 126.

The manner in which cap retaining collar assembly 90 and sealing capmeans 89 are removed is best described with relation to FIGS. 12-15.FIG. 12 is an elevational view taken along line 12--12 of FIG. 15. Anend view is thereshown of sealing cap means 89 and cap retaining collarassembly 90, the components of which have been previously described. Forpurpose of a clear illustration, the other components of leading sledassembly 32 have not been shown in FIG. 12.

Located about cap retaining collar assembly 90 is a cap removalapparatus assembly 148 which is attached to producing platform 128. Thecap removal apparatus 148 includes a frame 150 having vertical framelegs 152 and 154. A sliding cap retrieval frame 156 is slidably disposedupon vertical legs 152 and 154. First and second hydraulic cylinders 158and 160 are extendably connected between cap removal apparatus frame 150and cap retrieval frame 156 so that cap retrieval frame 156 may be moveddownward from the position shown in FIG. 12 by extension of pistons 162and 164 of hydraulic cylinders 158 and 160, respectively.

Cap retrieval frame 156 includes first and second prongs 166 and 168 forengaging first and second prong receiving holes 170 and 172,respectively, of tangential flange 98 of cap retaining collar assembly90.

The lowermost position of cap retrieval frame 156 with the prongs 166and 168 engaging flange 98 of cap retaining collar assembly 90 isillustrated in FIG. 13.

The next step is to shear the shear bolt 108, shown in FIG. 7,connecting the second and third arcuate collar portions 94 and 96 of capretaining collar assembly 90. This is best understood by viewing FIGS.15 and 7. The relative initial position betwen fluid connector assembly126 and scaling cap means 89 is approximately shown in FIG. 15.

The fluid connector assembly 126 is slidably mounted within a fluidconnector assembly frame 186 so that the fluid connector assembly 126may be moved toward manifold member 56 by extension of a hydrauliccylinder 187 connected between fluid connector assembly 126 and frame186.

When hydraulic cylinder 187 is extended, fluid connector assembly 126 ismoved toward manifold member 56 and engages a forward end 184 of slidingshear member 110 and pushes sliding shear member 110 toward capretaining collar assembly 90 so as to shear the shear bolt 108. Fluidconnector assembly 126 then is moved out of engagement with manifoldmember 56 by retracting hydraulic cylinder 187.

The cap retaining collar assembly 90 and sealing cap means 89 are thenlifted out of engagement with manifold means 56 by retracting thepistons 162 and 164 of hydraulic cylinders 158 and 160.

Generally, when the first one of the sealing cap means 89 is removed theflow line bundle 10 will at least partially fill with water and sink tothe ocean floor.

Next the fluid connector assembly 126 and manifold member 56 must beconnected for fluid communication therebetween. The construction of thefluid connector assembly 126 is best shown in FIGS. 16 and 17. FIG. 16is an end view taken along line 16--16 of FIG. 15.

It is noted that FIGS. 16 and 17 are only schematic illustrations offluid connector assembly 126. Fluid connector assembly 126 includes anannular body member 174 connected to an end frame 176 by hydraulic rams180 and 182.

Located within annular body 174 are a plurality of longitudinallyextending fingers 188 which are resiliently connected to fluid connectorassembly 126 so that the free ends of 190 of fingers 188 may bedeflected radially outward and inward.

Fluid connector assembly 126 includes an inner body 192 having aplurality of ports 189, 191, 193, 194, 195 and 196, for fluidcommunication with ports 55, 57, 59, 60, 61, and 62, respectively, ofmanifold member 56. A platform conduit bundle 197, as seen in FIG. 15,is connected at one end to the ports of fluid connector assembly 126 andhas a second end connector assembly 199 for connection to a riser tubeassembly (not shown) leading to the surface of the body of water 44.

Adjacent an end face 198 of inner body 192 is a metal gasket 200. Metalgasket 200 includes a plurality of holes 202 disposed therein forallowing alignment stubs 125 of inner body 192 to protrude therethrough.

Adjacent each of the ports 191 and 194 are frustoconical raised portions204 and 206 for sealing engagement with the ports 57 and 60,respectively, of manifold member 56. Similar frustoconical surfaces arelocated adjacent ports 189, 192, 195 and 196. Each of the frusto-conicalsections preferrably includes a resilient sealing ring (not shown)disposed therein as will be understood by those skilled in the art.

The free ends 190 of longitudinally extending fingers 188 all includeradially inward projecting tongue portions 208 which engage an annulargroove 210 disposed about a cylindrical outer surface of manifold member56. To lock fingers 188 into engagement with groove 210, the pistons ofhydraulic rams 180 and 182 are extended to the position shown in FIG.17, so that a tapered annular surface 209 of annular body 174 engagestapered radially outer surfaces 211 of fingers 188 and deflects fingers188 toward groove 210.

When tongue portions 208 engage groove 210, the manifold member 56 islocked in sealing engagement with metal gasket 200 so that fluidcommunication is provided between the conduits 12-22 and theirrespective ports within inner body 192 of fluid connector assembly 126through the ports of manifold member 56.

After the ends of the flow line bundle 10 have been connected to thesubsea wellhead (not shown) and the producing platform 128, it isdesirable to insure that all of the space between conduits 12-22 andouter tubular covering member 24 is completely filled with sea water.This is accomplished in the following manner.

As is seen in FIG. 5, a first valve means or bleed-off orifice 212 isconnected to tubular covering extension 82, and upon opening of firstvalve means 212 the space between conduits 12-22 and tubular covering 24is communicated with the body of water 44.

As is best seen in FIGS. 1 and 2, a second valve means 214 islongitudinally spaced from first valve means 212 away from leading sledassembly 32. Upon opening the second valve means the space betweenconduits 12-22 and outer covering 24 is placed in fluid communicationwith the body of water 44.

The purpose of having first and second valve means 212 and 214 is toinsure that all of the gases contained within the tubular covering 24may be easily bled off. The connections to the subsea wellhead assembly(not shown) and the producing platform 128 are typically locatedapproximately 10 feet above the ocean floor 46. Therefore, when themiddle portion of flow line bundle 10 is laying on the ocean floor thefirst valve means 212 is the high point in the bleed-off system. Seawater enters the second valve means 214 and gases within the coveringmember 24 escape through the first valve means 212. A similar bleed-offis performed at the other end of flow line bundle 10.

At about the same time that covering 24 is flooded, the buoyancy tanks52 and 54 of sleds 32 and 34 are also flooded.

Typically one of the relatively large conduits 12 and 14 is used toconduct hydrocarbons produced from the subsea well to the producingplatform. These hydrocarbons often have a temperature relatively higherthan that of the body of water 44 and of the other conduits and tubularcovering member disposed in the body of water.

By flooding the space between conduits 12-22 and covering member 24 withsea water, the heat from the relatively high temperature conduit, forexample conduit 12, is transmitted to the other conduits 14-22 and tothe outer covering member 24. The outer covering member 24 in turnconducts much of this heat outward to the body of water. The flooding ofthe space between conduits 12-22 and covering member 24 with waterprovides an advantage, as opposed to the situation which would existwith a similar system without the flooding, in that by transmitting heatfrom conduit 12 to the other conduits, the temperature of the conduitsis maintained much more nearly equal than would otherwise be the case,so that differences in thermal expansion of the conduits are minimized.Additionally by conducting heat to the tubular covering 24 and outwardinto the body of water 44, problems of thermal expansion are furtherreduced.

Thus, the flow line bundle and method of installing the same of thepresent invention are well adapted to carry out the objects and attainthe ends and advantages mentioned, as well as those inherent therein.While presently preferred embodiments of the invention have beendescribed for the purpose of this disclosure, numerous changes in theconstruction and arrangement of parts can be made by those skilled inthe art, which changes are encompossed with the spirit of this inventionas defined by the appended claims.

The embodiments of this invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. An off-bottom tow methodfor transporting a tubular member from one location to another within abody of water and clearing an obstacle present within said body ofwater, said method comprising the steps of:connecting a first flexibleline between a leading end of said tubular member and a towing means;connecting a second flexible line between a trailing end of said tubularmember and a retarding means; pulling said first flexible line forwardto pull said tubular member through said body of water; and increasing aretarding force applied to said second line, when approaching saidobstacle located in said body of water above said floor, to lift saidtubular member above said obstacle.
 2. The method of claim 1,wherein:said step of pulling said first flexible line is furthercharacterized as towing said first flexible line with a first poweredfloating vessel; and said step of increasing a retarding force isfurther characterized as increasing a reverse thrust of a second poweredfloating vessel attached to said second flexible line.
 3. An off-bottomtow method for transporting a tubular member from one location toanother within a body of water, said method comprising the stepsof:connecting a first flexible line between a leading end of saidtubular member and a first powered floating vessel; connecting a secondflexible line between a trailing end of said tubular member and a secondpowered floating vessel; and towing said first flexible line forwardwith said first powered vessel to pull said tubular member through saidbody of water; while maintaining said tubular member above a floor ofsaid body of water at a controlled depth below a surface of said body ofwater.
 4. The method of claim 3, wherein said step of maintaining isfurther characterized as maintaining said tubular member at a depthsufficiently small enough to allow said tubular member to clear anobstacle located within said body of water above said floor thereof.